Guest J D, Rao A, Olson L, Bunge M B, Bunge R P
The Miami Project to Cure Paralysis, The Organ Procurement Team, Department of Neurological Surgery, University of Miami School of Medicine, 1600 N.W. 10th Avenue, Miami, Florida 33136, USA.
Exp Neurol. 1997 Dec;148(2):502-22. doi: 10.1006/exnr.1997.6693.
Advances in the purification and expansion of Schwann cells (SCs) from adult human peripheral nerve, together with biomaterials development, have made the construction of unique grafts with defined properties possible. We have utilized PAN/PVC guidance channels to form solid human SC grafts which can be transplanted either with or without the channel. We studied the ability of grafts placed with and without channels to support regeneration and to influence functional recovery; characteristics of the graft and host/graft interface were also compared. The T9-T10 spinal cord of nude rats was resected and a graft was placed across the gap; methylprednisolone was delivered acutely to decrease secondary injury. Channels minimized the immigration of connective tissue into grafts but contributed to some necrotic tissue loss, especially in the distal spinal cord. Grafts without channels contained more myelinated axons (x = 2129 +/- 785) vs (x = 1442 +/- 514) and were larger in cross-sectional area ( x = 1.53 +/- 0.24 mm2) vs (x = 0.95 +/- 0.86 mm2). The interfaces formed between the host spinal cord and the grafts placed without channels were highly interdigitated and resembled CNS-PNS transition zones; chondroitin sulfate proteoglycans was deposited there. Whereas several neuronal populations including propriospinal, sensory, motoneuronal, and brainstem neurons regenerated into human SC grafts, only propriospinal and sensory neurons were observed to reenter the host spinal cord. Using combinations of anterograde and retrograde tracers, we observed regeneration of propriospinal neurons up to 2.6 mm beyond grafts. We estimate that 1% of the fibers that enter grafts reenter the host spinal cord by 45 days after grafting. Following retrograde tracing from the distal spinal cord, more labeled neurons were unexpectedly found in the region of the dextran amine anterograde tracer injection site where a marked inflammatory reaction had occurred. Animals with bridging grafts obtained modestly higher scores during open field [(x = 8.2 +/- 0.35) vs (x = 6.8 +/- 0.42), P = 0.02] and inclined plane testing (x = 38.6 +/- 0. 542) vs (x = 36.3 +/- 0.53), P = 0.006] than animals with similar grafts in distally capped channels. In summary, this study showed that in the nude rat given methylprednisolone in combination with human SC grafts, some regenerative growth occurred beyond the graft and a modest improvement in function was observed.
从成人外周神经纯化和扩增雪旺细胞（SCs）的进展，以及生物材料的发展，使得构建具有特定性质的独特移植物成为可能。我们利用聚酰胺/聚氯乙烯引导通道形成固态人雪旺细胞移植物，该移植物可带或不带通道进行移植。我们研究了带通道和不带通道植入的移植物支持再生和影响功能恢复的能力；还比较了移植物以及宿主/移植物界面的特征。切除裸鼠的T9 - T10脊髓，并在间隙处植入移植物；急性给予甲基强的松龙以减少继发性损伤。通道使结缔组织向移植物内的侵入减至最少，但导致了一些坏死组织的损失，尤其是在脊髓远端。不带通道的移植物含有更多有髓轴突（x = 2129 ± 785），而带通道的移植物有髓轴突数量为（x = 1442 ± 514），且不带通道的移植物横截面积更大（x = 1.53 ± 0.24 mm²），而带通道的移植物横截面积为（x = 0.95 ± 0.86 mm²）。宿主脊髓与不带通道植入的移植物之间形成的界面高度交错，类似于中枢神经系统 - 外周神经系统过渡区；硫酸软骨素蛋白聚糖沉积于此。虽然包括脊髓固有、感觉、运动神经元和脑干神经元在内的几个神经元群体再生进入人雪旺细胞移植物，但仅观察到脊髓固有神经元和感觉神经元重新进入宿主脊髓。使用顺行和逆行示踪剂组合，我们观察到脊髓固有神经元在移植物外再生达2.6 mm。我们估计，移植后45天时，进入移植物的纤维中有1%重新进入宿主脊髓。从脊髓远端进行逆行示踪后，意外地在葡聚糖胺顺行示踪剂注射部位区域发现了更多标记神经元，该部位发生了明显的炎症反应。与在远端封闭通道中植入类似移植物的动物相比，植入桥接移植物的动物在旷场试验[（x = 8.2 ± 0.35）对（x = 6.8 ± 0.42），P = 0.02]和斜面试验[（x = 38.6 ± 0.542）对（x = 36.3 ± 0.53），P = 0.006]中得分略高。总之，本研究表明，在给予甲基强的松龙的裸鼠中植入人雪旺细胞移植物后，移植物外发生了一些再生生长，并观察到功能有适度改善。
